Syntheses, structures and properties of two zinc(II) coordination complexes based on two bis(pyridyl)-bis(amide) ligands and 1,2-phenylenediacetic acid

Two new zinc(II) coordination complexes [Zn(pda)(3-bpcd)_0.5] (<b>1</b>) and [Zn(pda)(3-bpoa)]·H₂O (<b>2</b>) have been synthesized by self-assembly of 1,2-phenylenediacetic acid (H₂pda), semi-rigid/or flexible bis(pyridyl)-bis(amide) ligands [3-bpcd = N,N′-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, 3-bpoa = N,N'-bis(3-pyridyl)octandiamide] and zinc nitrate. Complex <b>1</b> is a 2 D layered framework derived from the 1 D [Zn(pda)]_2n ribbon-like chain and the bidentate 3-bpcd, which is a (3,4)-connected (4²·6³·8)(4²·6) topology, then the adjacent layers are linked by hydrogen bonds to build a 3 D supramolecular network. Complex <b>2</b> displays a 3 D framework based on the 1 D [Zn(pda)]_2n ribbon-like chains and the 1 D [Zn(3-bpoa)]_n chains, which represents a (3,5)-connected (4².6⁵.8³)(4².6) topology. Two bis(pyridyl)-bis(amide) ligands with different flexibilities play an important role in constructing final topological structures for title complexes. Moreover, the fluorescent properties of two zinc(II) complexes and their fluorescent sensing properties toward small solvent molecules have been studied. Additionally, the photocatalytic properties of complexes <b>1 </b>−<b> 2</b> toward the degradation of dyes have been investigated.

本研究通过1,2-苯二乙酸（H₂pda）、半刚性/柔性双吡啶双酰胺配体[N,N'-双(吡啶-3-基)环己烷-1,4-二甲酰胺（3-bpcd）与N,N'-双(3-吡啶基)辛二酰胺（3-bpoa）]以及硝酸锌的自组装反应，合成了两种新型二价锌配位配合物：[Zn(pda)(3-bpcd)₀.₅]（配合物1）与[Zn(pda)(3-bpoa)]·H₂O（配合物2）。配合物1为由一维[Zn(pda)]₂ₙ带状链与双齿配体3-bpcd构筑的二维层状骨架，其拓扑类型为(3,4)连接的(4²·6³·8)(4²·6)；相邻层间通过氢键相互作用构筑得到三维超分子网络。配合物2则以一维[Zn(pda)]₂ₙ带状链与一维[Zn(3-bpoa)]ₙ链为基础，构建出三维骨架，其拓扑类型为(3,5)连接的(4²·6⁵·8³)(4²·6)。两种具有不同柔性的双吡啶双酰胺配体，对目标配合物的最终拓扑结构构筑发挥了重要作用。此外，本研究还考察了这两种二价锌配合物的荧光性能及其对小分子溶剂的荧光传感性能；同时探究了配合物1~2对染料降解的光催化性能。